Comment by vdqtp3

> Metadata is specifically available "for free" (who calls/messages whom when).

That's completely incorrect. Signal has only the following data (backed up by what they have provided when served warrants[1], and what internal FBI documents state about Signal[2]:

    Date and time a user registered.
    Last date of a user’s connectivity to the service.

[1] https://signal.org/bigbrother/central-california-grand-jury/

[2] https://propertyofthepeople.org/document-detail/?doc-id=2111...